Interactive Java Tutorials

Krypton-Argon Lasers

Air-cooled lasers using krypton-argon mixtures have become popular in confocal microscopy when several illumination wavelengths are required for dual or multiple-fluorophore studies. Such mixed-gas lasers are only capable of producing stable output on major lines that are well separated in the wavelength spectrum. Of the three laser lines typically utilized for confocal microscopy, the 488-nanometer and 568-nanometer lines have approximately equal power (10 to 15 milliwatts), while the 647-nanometer line has about 50 percent more (15 to 25 milliwatts). This interactive tutorial simulates the three major spectral lines produced by an krypton-argon mixed-gas laser.

The tutorial initializes with the gas laser tutorial speed set to Medium, a level that enables the visitor to observe the slow build-up of light in the laser cavity as it is reflected back and forth through the Brewster windows and mirrors. In order to operate the tutorial, translate the Laser Wavelength slider between the various available blue, yellow, and red laser spectral lines (488, 568, and 647 nanometers), and observe how the color of the output beam changes with wavelength. Use the Tutorial Speed slider to adjust the speed of light oscillations within the laser cavity and the level of light emitted through the output lens.

The krypton-argon gas ion lasers commonly employed in confocal microscopy have an output range of approximately 10-15 milliwatts, with each spectral line averaging 3 to 5 milliwatts in power. The individual wavelengths can be mixed together (to form a simulation of "white" illumination for transmitted light experiments) or used alone with the appropriate interference filters to provide well-separated excitation wavelengths for single, double, and triple fluorophore investigations. These lasers typically produce near-diffraction limited TEM(0,0) output, demonstrate high stability with low noise, and have a reasonably long lifespan. Another advantage is the small footprint, which is useful in situations where space is limited.